Electeioal detonator



(No Model.)

O. H. RUDD.

ELEGTRIGAL DETONATOR.

No. 556,903. Patented Mar. 24, 1896.

*i 3 Ham Z65 ave 1 m? UNITED STATES PATENT OFFICE.

CHARLES H. RUDD, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE VVES'IERN ELECTRIC COMPANY, OF SAME PLACE.

ELECTRICAL DETO NATO R.

SPECIFICATION forming part of Letters Patent No. 556,903, dated March 24, 1896.

Application filed February 3, 1894. Serial No. 498,987. (No modelh To all whom it may concern:

Be it known that I, CHARLES II. RUDD, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Electrical Detonators, (Case No. 5%,) of which the following is a full, clear, concise, and exact description, reference being hadto the accompanying drawings, forming a part of this specification.

My invention relates to electrical detonators; and its object is to effect the firing of explosive material by electricity and to reduce to a minimum the amount of wiring neces- 1 5 sary for carrying the current.

In an application, Serial No. 494,7 25, filed December 27, 1893, I have described an explosive cartridge comprising an explosive material in which are embedded conductors of electricity through which an electric current may be passed to raise the explosive material to a desired temperature, at which time an igniter, comprising a wire adapted to be heated to an igniting temperature, is adapted to fire the explosive material. In an application, Serial No. 498,988, filed February 3, 1894, I have described and claimed broadly means for connecting the heating and igniting conductors in a single circuit, and my in- 0 vention herein embodies a specific form of said broad invention, and so far as matter shown herein is covered by the claims of said application, this application is to be consid cred subsidiary thereto.

My invention in its preferred form comprises an igniting-conductor normally located in a parallel branch of the circuit and so adjusted that under normal conditions the current diverted therethrough is insufiicient to 0 raise the temperature to the igniting degree,

means being provided for increasing the resistance of that portion of the circuit with Which said igniting-conductor is in parallel when it is desired to fire the cartridge,thereby 5 increasing the strength of the current traversing the igniting-conductor and raising the temperature of the same to the igniting degree.

I preferably secure the increase of resist- 5o ance of the parallel portion of the circuit by providing a soft-iron core surrounded by a helix adapted to be traversed by the current to impart polarity to the soft-iron core, an armature of soft iron or of steel being placed opposite the pole of the c0re,the circuit of the 5 5 parallel portion of the circuit being through the surface of contact of the armature and core. The resistance of the parallel portion of the circuit is such that the current diverted through the igniting-conductor is insufficient to raise the temperature of the same to the igniting degree. \Vhen it is desired to fire the explosive material, the direction of the current is reversed, thus changing the polarity of the soft-iron core which kicks the armature, 6 5 since the magnetic inertia of the soft-iron armature prevents the immediate reversal of its magnetism, while the steel armature assumes permanent polarity, corresponding to the original polarity of the iron core. The repulsion of the armature may serve to decrease the force of contact between the armature and core, thus increasing the resistance of the parallel portion of the circuit, or it may break the contact between the armature and the core entirely, thus increasing the resistance to infinity.

I will describe my invention more in detail in connection with the accompanying drawings, in which- Figure 1 is a diagrammatic view of several cartridges connected for-firing after the manner of my invention. Fig. 2 is a diagrammatic view of the igniting mechanism. Fig.

3 is a detail view of a preferred form of ignitin g mechanism. Fig. 4 is a sectional view of a cartridge embodying my invention.

Like letters refer to like parts in the several figures.

Each of the cartridges a a is provided with o heating-coils b I), through which current is adapted to be passed to raise the temperature of the explosive material to the required der gree. In series with the heating-coil bis provided a helix 0, which surrounds a core of 5 soft iron d. The circuit, continuing, passes through the igniting-conductor e. The end of helix 0 is in electrical contact with the iron core (1, while the armature his in electrical contact with the circuit beyond the igniting-conduc- 10o tor e, so that when the armature is in contact with theiron core the ignitingconductor is d, the igniting-conductor e is shunted and shunted by the parallel branch through the iron core and the. armature. The armature maybe made of soft iron or of material, such as steel, capable of assuming permanent magnetism, and is normally held against the end of the iron core by a piece 70 of parafline, solder, or the like, which will'readily fuse under the influence of heat. i

\Vhen it is desired to fire the cartridges, current is turned on, traversing, the heatingcoils b b and raising the temperature of the explosive material to the required degree. The armature h resting against the iron core the current passing therethrough is insuflicient to raise the same to the igniting temperature. The passage of the current through the helix 0 imparts polarity to the soft-iron core (Z, which attracts the armature h. The

armature It also assumes magnetic polarity, though the polarity when of steel is permanent. The heating of the explosive material by the heating-coils and the passage of the current through the armature cause the fusion of the paraffine k, and thus leaving the armature suspended from the end of the iron core d.

When it is desired to ignite the explosive material, the current is reversed by a reversing-switeh l. The reversal of theeurrent reverses the polarity of the iron core (I, causing it to repel the magnetized armature h.

When the armature is of steel or other permanently-magnetizable material, it assumes polarity under the influence of the the polarity of the core is changed the armatureis permanently repelled.

When a soft-iron armature is used, it asder the influence of the original polarity of the iron core; but when the polarity of the core is reversed by the reversal of the current the magnetic inertia of the armature prevents the reversal of the polarity of the armature in unison with the reversal of the polarity of the core, and consequently at the instant the magnetism of the core has fallen to zero and changes sign, the magnetism of the armature being of the original sign, the armature is repelled. The repulsion of the armature h traverse the igniting-conductor to raise the temperature to the igniting degree and cause the explosion of the explosive material.

the firing as within the purview of my invention, broadly considered.

When the soft-iron armature is used, it is not necessary to employ a reversing-switch, as a circuit-breaking switch may be used to open the circuit and de-energize the soft-iron core, which will thus release its armature and open the shunt-circuit about the ignitingconductor. The circuit may then be closed by the switch, and the whole current necessarily traversing the igniting-conductor the same is brought to the fusing temperature to fire the explosive material.

In Fig. 3 I have illustrated an economical manner of arranging the igniting mechanism. Between the ends of a U -shaped piece of mag netic material m may be arranged in line the soft-ironeore d, the armature h, and the fusible material It. Upon the passage of the current the fusible material is fused; but the atltraction between the magnetic material 'm and the end of the iron core d maintains the core and armature in position until the eurrent is reversed, when the armature iskicked from the end of the core.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is-- 1. The combination with explosive material, of an igniting-conduetor in an electrical circuit, a shunt or by-path about said igniting-conductor, and means for increasing the resistance through said by-path to cause an 1 increased current to flow through said igniting-conductor; substantially as described. original polarity of the iron core, so that when 2. The combination with explosive matcrial, of an igniting-eonductor in an electrical circuit, a shunt or- Dy-path about said ignitingeonductor, and means for opening the cirsumes polarity, though not permanent, un-

euit through saidv by-path to cause an increased flow of current through said ignitingconductor; substantially asdescribed.

3. The combination with explosive material, of an. igniting-conductor in an electrical 4 circuit, a shunt or by-path about said igniting-conductor, and means operated by the reversal of the current in said circuit for increasing the resistance through said by-path to cause an increased flow of current through the igniting-conductor; substantially as de- 1 scribed. breaks the shunt-circuit around the igniting- E conductor, thus causing all of the current to 4. The combination with explosive material, of an igniting-conductor and a helix included in an electric circuit, a soft-iron eore encircled by said helix, an armature normally resting against said core and completing a parallel circuit about said igniting-conduetor, and means for reversing the current through said helix; substantially as described.

5. The combination (vith explosive material, of an igniting-conductor e, a helix 0, a

soft-iron core encircled by said helix, a permanentiy-magnetizable armature h normally resting against said iron core and completing a parallel circuit about said igniting-conduc- 1o material k; said core (1, armature h and fusible material 70 being situated between the ends of said piece m; substantially as described.

In witness whereof I hereunto subscribe my name this 26th day of January, A. D. 1894.

CHARLES H. RUDD. Witnesses:

W. CLYDE JONES, GEORGE L. CRAGG. 

